Hyperactive boys will be treated with up to 15 mg/day of Clorgyline selective Monoamine Oxidase A inhibitor, or amphetamine (0.5 mg/kg). Behavioral measures include Activity, Vigilance and Parent and Teacher Behavior Ratings. Biological measures include Urinary MHPG, PEA, and Platelet MAO. The aim of the study is to elucidate neurotransmitter mechanism in amphetamines efficacy in hyperactivity.